A prior art laser using such pumping sources includes certain essential items in common, at least with respect to their functions mentioned below, with a laser of the present invention.
These essential items in common are the following:
a laser slab having two main faces each having two edges which extend along a longitudinal direction and which are separated in a transverse direction by the width of said slab, said slab also having thickness in a pumping direction and sections in the transverse direction and the pumping direction, the material of said slab being suitable for being excited by pumping light arriving along said pumping direction in order to amplify light to be amplified and propagating along said longitudinal direction;
at least one pumping source facing at least one of said main faces in order to deliver said pumping light distributed over said longitudinal direction, each of said sources emitting said light via an emitting area which is narrow relative to said plate, at least in said transverse direction; and
a reflector system suitable for reflecting said pumping light so as to avoid losses.
One such prior art laser is described in the article: "Diode-laser-array-pumped neodymium slab oscillators," by M. K. Reed, W. J. Kozlovsky, R. L. Byer, G. L. Harnagle, and P. S. Cross, published in Optics Letters, Vol. 13, No. 3, March 1988.
The reflector of this laser is constituted by a simple mirror disposed facing one of the main faces of the plate, namely the face opposite to the face which is illuminated by the pumping sources. It serves to increase the overall energy efficiency of the laser by reducing losses of pumping light to the outside of the laser.
Nevertheless, it remains desirable to increase the efficiency of such a a laser further, and/or to increase the light power which it is capable of delivering.
Particular aims of the present invention include increasing the uniformness of pumping while avoiding losses of pumping light to the outside of such a laser, and while enabling the slab to be cooled.